To clarify, the prices I found online for the Sirius docking station were retail prices. We certainly don't expect Winnebago to charge customers less than that! But, they charged us nearly twice average retail. And, lest we forget, charged 2.5 hours labor to install it. Sounds like a very profitable profit center!
Back to the problem, an option that was never presented to us, but probably would have been worth exploring is simply removing the "plug and play". We've never taken it out of the docking station to use in the Jeep, so we're not really using that feature, anyway. The in-dash radio is Sirius-ready on its own. So, we're wondering what would happen if the plug-and-play was unplugged. Couldn't a person wire the antenna to the in-dash radio and be back in business?
But, we'll never know. Instead, we're enjoying tunes on our pricey replacement.
Update: Just got off the phone with our extended warranty company. The rep reported that their reimbursement for product replacement is Manufacturer's Suggested Retail Price. (Sounds fair!) On the Sirius docking kit, the MSRP is $69.99. Winnebago Factory Service charged us $145.21.